by Kastro
Paper/Archive/CVE-2026-4716

CVE-2026-4716

Mozilla Firefox — Incorrect boundary conditions, uninitialized memory in the JavaScript Engine component

EPSS 0.4%CVSS 9.1
critical.is priorityof 100
35
CVSS 9.1 (ADP, NVD agree)9.1 / 10 × 3027.3Not in CISA KEV+300.0EPSS percentile 36.6.366 × 207.3No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

Incorrect boundary conditions, uninitialized memory in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

Affected

ProductAffectedFixed inSource
Firefoxsee advisory140.9CNA
Thunderbirdsee advisory140.9CNA

Scores by source

CISA ADP9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
NVD9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: partial

References

refbugzilla.mozilla.org/show_bug.cgi?id=2018592refmozilla.org/security/advisories/mfsa2026-20refmozilla.org/security/advisories/mfsa2026-22refmozilla.org/security/advisories/mfsa2026-23refmozilla.org/security/advisories/mfsa2026-24